Showing papers in "Acta Anaesthesiologica Scandinavica in 2000"

Cognitive dysfunction 1-2 years after non-cardiac surgery in the elderly. ISPOCD group. International Study of Post-Operative Cognitive Dysfunction.

Abstract: Background: Postoperative cognitive dysfunction (POCD) is a well-recognised complication of cardiac surgery, but evidence of POCD after general surgery has been lacking. We recently showed that POCD was present in 9.9% of elderly patients 3 months after major non-cardiac surgery. The aim of the present study was to investigate whether POCD persists for 1–2 years after operation. Methods: A total of 336 elderly patients (median age 69 years, range 60–86) was studied after major surgery under general anesthesia. Psychometric testing was performed before surgery and at a median of 7, 98 and 532 days postoperatively using a neuropsychological test battery with 7 subtests. A control group of 47 non-hospitalised volunteers of similar age were tested with the test battery at the same intervals. Results: 1–2 years after surgery, 35 out of 336 patients (10.4%, CI: 7.2–13.7%) had cognitive dysfunction. Three patients had POCD at all three postoperative test sessions (0.9%). From our definition of POCD, there is only a 1:64 000 likelihood that a single subject would have POCD at all three test points by chance. Logistic regression analysis identified age, early POCD, and infection within the first three postoperative months as significant risk factors for long-term cognitive dysfunction. Five of 47 normal controls fulfilled the criteria for cognitive dysfunction 1–2 years after initial testing (10.6%, CI: 1.8–19.4%), i.e. a similar incidence of age-related cognitive impairment as among patients. Conclusion: POCD is a reversible condition in the majority of cases but may persist in approximately 1% of patients.

Evaluation of three risk scores to predict postoperative nausea and vomiting.

Abstract: Background: So far there are three different scores to predict postoperative vomiting (PV: Apfel et al., 1998) or postoperative nausea and vomiting (PONV: Koivuranta et al., 1997; Palazzo and Evans, 1993). All three scores used logistic regression analysis to identify and create weights for the risk factors for PV or PONV. In short, these were sex, age, history of previous PONV, motion sickness, duration of anaesthesia, and use of postoperative opioids. However, an external evaluation and a comparison of these scores has not been performed so far. Methods: Patients undergoing a variety of surgical procedures under general anaesthesia were studied prospectively. Preoperatively, they completed a questionnaire concerning potential risk factors for the occurrence of PV or PONV implemented in the three risk scores. Balanced anaesthesia (induction agent, non-depolarising neuromuscular blocker, opioid, and inhalation agent in nitrous oxide/oxygen) was performed. No intravenous anaesthesia or any antiemetic prophylaxis was applied. Postoperatively, the patients were observed in the recovery room for the occurrence of PV and PONV and were visited twice on the ward within the 24-h observation period. Both the patients and the nursing staff were asked whether PV or PONV was present. The severity of PONV was categorised using a standardised scoring algorithm. A total of 1444 patients was finally included into the analysis. Using information of the predicted risk for the individual patients and the actual occurrence of PV or PONV, Receiver Operator Characteristics (ROC-curves) were drawn. The area under each ROC-curve was calculated as a means of the predictive properties of each score and was compared for statistical differences. Results: For prediction of PONV (any severity) the AUC-values (AUC=area under the curve) and the corresponding 95%-confidence intervals were: Apfel: 0.70 (0.67–0.72); Koivuranta: 0.71 (0.69–0.73); Palazzo: 0.68 (0.65–0.70). For prediction of PV: Apfel: 0.73 (0.71–0.75); Koivuranta: 0.73 (0.70–0.75); Palazzo: 0.68 (0.65–0.70). Thus, all three scores appeared to have a moderate accuracy as measured by the AUC. The score of Koivuranta predicts PONV (P=0.007) and also PV (P=0.002) significantly better than Palazzo’s score. Furthermore, for predicting of PV the score of Apfel was also superior to Palazzo’s score (P=0.005). All three scores predict PV with the same accuracy as PONV. Conclusion: The occurrence of PV and PONV in patients undergoing surgery under balanced anaesthesia can be predicted with moderate but acceptable accuracy using one of the available risk scores, regardless of local surgical or anaesthesiological circumstances. For clinical practice, we recommend the score published by Koivuranta, since its calculation is very simple.

Effects of conventional physiotherapy, continuous positive airway pressure and non-invasive ventilatory support with bilevel positive airway pressure after coronary artery bypass grafting.

Abstract: BACKGROUND: Coronary artery bypass graft (CABG) surgery with the use of mammary arteries is associated with severe alteration of lung function parameters The purpose of the present study was to compare the effect on lung function tests of conventional physiotherapy using incentive spirometry (IS) with non-invasive ventilation on continuous positive airway pressure (CPAP) and with non-invasive ventilation on bilevel positive airway pressure (BiPAP or NIV-2P), METHODS: Ninety-six patients were randomly assigned to 1 of 3 groups: NIV-2P (1 h/3 h), CPAP (1 h/3 h) and IS (20/2 h) Pulmonary function tests and arterial blood gases analyses were obtained before surgery On the 1st and 2nd postoperative days, these parameters were collected together with cardiac output and calculation of venous admixture RESULTS: For the 3 groups a severe restrictive pulmonary defect was observed during the 1st postoperative day On the 2nd postoperative day, in opposition to IS, intensive use of CPAP and NIV-2P reduced significantly the venous admixture (P<0001) and improved VC, FEV1 and PaO2 (P<001) CONCLUSION: We conclude that preventive use of NIV can be considered as an effective means to decrease the negative effect of coronary surgery on pulmonary function

Non-opioid postoperative analgesia.

Abstract: Although significant improvement has been made in the treatment of pain in the postoperative period, many patients still experience unnecessary discomfort resulting in distress, higher morbidity and prolonged stay in hospital. The standard pillar of postoperative treatment of severe pain is the use of opioids. However, adverse reactions to opioids make their use unfavourable. A better understanding of the pathophysiology of pain has helped clinicians to a more balanced approach to postoperative pain treatment. The development of the multimodal approach to postoperative analgesia, with the use of different drugs acting via different routes to give good analgesia, with minimal side-effects, represents a major development in the treatment of postoperative pain. Early, aggressive mobilisation and feeding must follow in order to restore normal conditions quickly. Alternatives to opioids should be used as extensively as possible. Local anaesthesia, used as regional blocks or as wound infiltration, is most beneficial. Paracetamol has good basic analgesic properties, and should probably be used in dosages higher than recommended today. The combination with a NSAID results in better and longer-lasting analgesia. The intravenous form propacetamol will increase the possibilities of its use. The new concept of selective COX-2 inhibiting NSAIDs will result in analgesic and anti-inflammatory drugs with fewer side-effects. The well-known inexpensive group of corticosteroids have good analgesic and anti-emetic properties, and are especially interesting to use in patients who do not tolerate NSAIDs. The alpha2-receptor agonists like clonidine, when administered epidurally or intrathecally, are useful adjuncts, but their adverse effects on sedation and hypotension limit their use. NMDA-receptor antagonists are of limited value in the postoperative period. Adenosine and neostigimine are still on a research level but may lead to new, clinically useful analgesic drugs. In the future, cannabinoids, cholecystokinin-receptor antagonists and neurokinin-1 antagonists may become important analgesic drugs.

Assessment of postoperative nausea using a visual analogue scale.

Abstract: Background Assessment of postoperative nausea intensity is difficult because nausea is a subjective and unpleasant sensation. We propose using the Visual Analogue Scale (VAS) device to increase the efficiency and precision in the assessment of nausea. We carried out a pilot study on postoperative patients suffering from nausea to measure the degree of agreement between the VAS scores and those given on a 4-point verbal descriptive scale (VDS). Methods Postoperative nausea was evaluated by means of a classical VAS (0-10 cm) device and a 4-point VDS (0=no nausea, 1=mild, 2=moderate, 3=severe) in 128 surgical spontaneously complaining patients. Evaluation was repeated 45 min after rescue medication given if nausea was intractable, lasted more than 10 min or at the request of the patient. Ordinal logistic regression was used to measure the association between VAS and VDS and to determine cut-off points on the VAS. Results The VAS device was easily understood and used by patients. VAS scores decreased significantly from 5.5+/-2.3 to 1.4+/-1.8 after rescue medication (P=0.002). Application of ordinal logistic regression to pre- and post-medication data combined yielded an agreement of 86% between VAS and VDS and the cut-off points on the VAS were estimated as follows: 0-1 (no nausea), 1+/-4 (mild), 4+/-7 (moderate) and 7+/-10 (severe). Conclusion The VAS method proved to be useful for assessing quantitative nausea intensity and for testing the efficacy of rescue medication. It was found that a cut-off value of 4 on the VAS may be considered as a critical threshold triggering anaesthesiologists or nurses to administer rescue medication.

Tracheal intubation without the use of muscle relaxants: remifentanil or alfentanil in combination with propofol

Abstract: Background: Alfentanil-propofol combination provides adequate conditions for tracheal intubation without neuromuscular blocking drugs in most patients. Providing an option for intense opioid effect without compromising recovery after short operations, remifentanil might offer benefits over alfentanil, especially in ambulatory surgery. In this study intubating conditions after remifentanil-propofol were compared to those after alfentanil-propofol. Methods: In a randomized, double-blind study 60 healthy patients were assigned to one of three groups (n=20). After intravenous atropine, remifentanil 3 or 4 μg kg−1 (Rem3 or Rem4) or alfentanil 30 μg kg−1 (Alf30) was injected over 30 s followed by propofol 2.5 mg kg−1. Sixty seconds after the administration of propofol, laryngoscopy and intubation were attempted. Intubating conditions were assessed as excellent, good or poor on the basis of ease of ventilation, jaw relaxation, position of the vocal cords, and patient response to intubation and slow inflation of the endotracheal tube cuff. Results: Overall conditions at intubation were significantly (P<0.05) better, and the frequency of excellent conditions was significantly (P<0.05) higher in the Rem4 group compared with the Alf30 group. Intubation was judged to be impossible in 20%, 25% or 5% of the patients in the Alf30, Rem3 or Rem4 groups, respectively. No patient manifested signs of opioid-induced muscular rigidity. In terms of arterial pressures or heart rate, there were no differences between the groups. Conclusion: The best method was the combination of remifentanil 4 μg kg−1 and propofol 2.5 mg kg−1. This provided satisfactory intubating conditions in 93%, and prevented cardiovascular intubation response.

Local infiltration with NSAIDs for postoperative analgesia: evidence for a peripheral analgesic action

Abstract: Background: In order to investigate the evidence for a peripheral analgesic effect of local infiltration with nonsteroidal anti-inflammatory drugs (NSAIDs) in postoperative pain, we conducted a systematic review. Methods: Randomised controlled and double-blind trials were evaluated. Outcome measures were pain scores, the use of supplementary analgesics, and time to first analgesic request. Efficacy was estimated by significant difference (P<0.05) as reported in the original reports and by calculation of the weighted mean difference of pain scores between treatment groups. Results: Sixteen studies with data from 844 patients were considered appropriate for analysis. The NSAIDs were administered as intra-articular injections, as components of intravenous regional anaesthesia (IVRA), and by wound infiltration and were compared with systemic administration or placebo. In the four studies comparing intra-articular NSAIDs with systemic administration a statistically significant effect in favour of intra-articular NSAIDs was found. Only one study compared IVRA NSAID with systemic administration, showing a significant effect in favour of IVRA administration. No more than two of the five studies comparing intrawound NSAIDs with systemic administration showed significant effect after intrawound administration. Most of the studies comparing local infiltration with placebo showed significant effect in favour of local infiltration. Conclusion: There is evidence for a clinically relevant peripheral analgesic action of intra-articular NSAIDs while results of IVRA and wound infiltration with NSAIDs in postoperative pain are inconclusive. Trials without a systemic control group were not considered to provide evidence for a local effect.

Quality of recovery in children: sevoflurane versus propofol.

Abstract: Background Sevoflurane, with its low pungency and low blood and tissue solubility, is an attractive anaesthetic in paediatric outpatient surgery. Propofol-anaesthesia is recognised for its rapid and clear-headed emergence. This study was designed to compare emergence and recovery characteristics of sevoflurane and propofol anaesthesia for tonsillectomy in children. Methods Children aged 3-10 years, undergoing elective tonsillectomy, were randomly assigned to receive propofol (n=25, induction with 3 mg x kg(-1), maintenance with 100-250 microg x kg(-1) min(-1)) or sevoflurane anaesthesia (n=25, induction 7 vol.%, maintenance 2-3 vol.%). Tracheal intubation was performed with alfentanil 20 microg x kg(-1) and atracurium 0.5 mg x kg(-1). Ventilation was controlled to maintain normocapnia and all patients received N2O/O2 (60:40 vol.%) for induction and maintenance of anaesthesia. At the end of surgery infiltration of the operative sites with bupivacaine 2 mg x kg(-1) was provided for postoperative analgesia. Emergence, recovery, discharge times, and incidence of side effects were compared between the two groups. Results Time to extubation (14 vs 15 min), time to response to simple verbal command (21 vs 21 min) and time to discharge from the recovery room (45 vs 50 min) were similar in the sevoflurane and propofol groups, respectively. There was a significantly greater incidence of postoperative agitation in the sevoflurane group (46%) compared with the propofol group (9%) (P=0.008). This did not, however, delay discharge from the recovery room. The incidence of nausea and vomiting was not significantly different (8% vs 0%; P=0.49). Conclusion In children, recovery from anaesthesia with sevoflurane results in a higher incidence of agitation compared with propofol.

Adenosine and cardioprotection during ischaemia and reperfusion--an overview.

Abstract: Adenosine is a local hormone, with numerous tissue-specific biological functions. In the myocardium, adenosine is released in small amounts at constant basal rate during normoxia. During ischaemia the production of adenosine increases several fold due to breakdown of adenosine triphosphate (ATP). Increased production of adenosine causes coronary vasodilatation. Thus, adenosine couples myocardial metabolism and flow during ischaemia and is called a homeostatic or "retaliatory metabolite". Furthermore, adenosine has electrophysiological effects in supraventricular tissue, causing a decrease in heart rate. In 1985 it was discovered that adenosine also exerts cardioprotective effects directly on cardiomyocytes. The aim of this review is to give an overview of the role of adenosine as a directly cytoprotective agent during myocardial ischaemia and reperfusion. We will focus on its effects on the myocytes, elicited by stimulation of adenosine receptors in sarcolemma, which triggers intracellular signalling systems. We will also address the new aspect that adenosine can influence regulation of gene expression. There is evidence that the myocardium is capable of endogenous adaptation in response to ischaemia, namely "hibernation" and early and late phases of "preconditioning". Endogenous substances produced during ischaemia probably trigger these responses. We will discuss the role of adenosine in these different settings. Adenosine can be given exogenously through intravasal routes; however, this review will also focus on the effects of endogenously produced adenosine. We will discuss pharmacological ways to increase endogenous levels of adenosine, and the effects of such interventions during ischaemia and reperfusion. Finally, we will review results from studies in humans together with relevant experimental studies, and indicate potential therapeutic implications of adenosine.

Prevention of post-herpetic neuralgia : Acyclovir and prednisolone versus epidural local anesthetic and methylprednisolone

Abstract: Background: Treatment of herpes zoster (HZ) includes the use of acyclovir with or without steroids. An alternative therapy is the epidural administration of local anesthetics with or without steroids. This trial compared the efficacy of these two treatment regimens in the prevention of post-herpetic neuralgia (PHN). Methods: Six hundred adults over 55 years of age with a rash of less than 7 days duration, and severe pain due to HZ, were enrolled and randomized to receive either intravenous acyclovir (10 mg/kg three times daily) for 9 days„prednisolone (60 mg per day with progressive reduction) for 21 days, or 6‐12 ml bupivacaine (0.25%) every 6‐8 or 12 h„methylprednisolone 40 mg every 3‐4 days by epidural catheter during a period ranging from 7 to 21 days. Efficacy was evaluated at 1, 3, 6 and 12 months. PHN was assessed as pain and/or allodynia, and ‘‘abnormal sensations’’ (hypoesthesia, burning, itching, etc.). Statistical analysis was performed based on the intent-to-treat population. Results: In the 485 patients who completed the study, the inci

Effects of carbon dioxide pneumoperitoneum for laparoscopic cholecystectomy.

Abstract: LAPAROSCOPY is ‘‘the golden standard’’ in treating symptomatic gallstones. Because the postoperative benefits are superior to open cholecystectomy, laparoscopy is today also used in patients with underlying diseases. To be able to treat this challenging patient population, we should be aware of physiological alterations caused by carbon dioxide (CO2) insufflation and elevated intra-abdominal pressure (IAP). It is now commonly accepted that pneumoperitoneum causes intraoperative adverse cardiovascular, respiratory and renal effects. Some of these effects are related to CO2 and some to elevated IAP. CO2 is the preferred gas for the creation of pneumoperitoneum because it is inexpensive, highly soluble, chemically stable, rapidly eliminated, physically inert, suppresses combustion and also provides fairly good illumination. CO2 is a normal product of human metabolism and at physiological levels non-toxic.

Diclofenac or acetaminophen for analgesia in paediatric tonsillectomy outpatients.

Abstract: Background: In order to establish an effective drug regimen, we compared the analgesic efficacy of oral diclofenac and high-dose acetaminophen on pain after tonsillectomy. Methods: In this randomised, double-blind study 48 children, 5 to 15 years of age, following tonsillectomy were assigned to receive either diclofenac 2-3 mg kg -1 24 h -1 (n=24) or acetaminophen 90 mg kg -1 24 h -1 (n=24) for the first three days after surgery. Postoperative pain was assessed by self-report each day before scheduled medication at 7 h, 12 h, 18 h and 23 h. Results: The number of children rating severe pain was high in both the diclofenac group, 5-50%, and in the acetaminophen group, 12-58%, during the three day study period. Pain scores in the diclofenac group were only significantly lower at 12 h on day 1-3 compared to pain scores in the acetaminophen group (P<0.05). None of the children in the diclofenac group experienced any episodes of nausea/vomiting compared to 9 children in the acetaminophen group on day 1. The incidences of nausea/vomiting increased with pain (P<0.05). None of the 48 children experienced any episodes of bleeding. Conclusions: This study indicates that diclofenac was no more effective than high-dose acetaminophen (90 mg vs. 60 mg kg -1 24 h -1 ) for analgesia, but resulted in a lower incidence of nausea and vomiting in patients following tonsillectomy.

Coagulation effects of a recently developed hydroxyethyl starch (HES 130/0.4) compared to hydroxyethyl starches with higher molecular weight.

Abstract: Background: Hydroxyethyl starches (HES) are known to interfere with blood coagulation according to molecular weight, the degree of substitution and the C2/C6 ratio. A recently developed low molecular hydroxyethyl starch (HES 130/0.4) was designed to reduce the blood compromising potency. Methods: In this study, effects of a 30% in vitro haemodilution with the new HES preparation (HES 130/0.4) in comparison to HES 200/0.5, HES 450/0.7 and sodium chloride solution were investigated using intrinsic and extrinsic activated thrombelastography (TEG) and plasmatic coagulation tests. Results: Whereas plasmatic tests revealed no prolongation of coagulation by HES in comparison to sodium chloride, the TEG variables clotting time, clot formation time and maximal clot firmness showed a significant (P<0.05) inhibition by all the HES preparations. The inhibition was most pronounced in HES 450 (P<0.05 vs HES 130) while HES 130 did not show a statistically significant difference in extrinsic activated maximal clot firmness when compared to sodium chloride. Conclusion: These in vitro results demonstrate that hydroxythyl starches especially compromise clot polymerisation. The new preparation HES 130/0.4 seems to inhibit platelet function to a lesser extent than hydroxyethyl starch preparations with a higher molecular weight and degree of substitution.

Anaphylactic reactions during induction of anaesthesia using rocuronium for muscle relaxation: a report including 3 cases.

Abstract: Anaphylaxis during induction of anaesthesia is a dreaded complication with a mortality rate of 3-6%, most frequently associated with the use of muscle relaxants. Current knowledge on this matter is reviewed in relation to the presentation of 3 cases of anaphylaxis and bronchospasm associated with the use of the recently released nondepolarizing muscle relaxant rocuronium. Bronchospasm may be the sole sign of a serious drug reaction, triggered by precipitation of insoluble thiopental crystals when mixed with a muscle relaxant in the intravenous (iv) line. It is recommended that these drugs are administered via different injection ports. The hypotension requires immediate treatment with oxygen, epinephrine and large amounts of iv fluids. Epinephrine infusion may be needed for hours. It is recommended that serum tryptase is measured approximately 2 h after debut of the serious drug reaction. Allergy testing should be performed for all the drugs the patient was exposed to, 4-8 weeks after the incident, and due to cross-reactivity, including all available muscle relaxants. Doctors are urged to inform their patients, and systematically register adverse drug reactions.

Effects on the bispectral index during medium-high dose fentanyl induction with or without propofol supplement

Abstract: Background: The search for a drug-independent monitor to determine depth of anaesthesia and hypnosis continues. The bispectral analysis (BIS) of the EEG correlates well with the clinical dose–response of hypnotic drugs during induction, but the effect on BIS of an opiate induction, as for coronary bypass surgery, is not known. Methods: Fourteen patients scheduled for elective coronary bypass surgery were studied. BIS was recorded during induction in 7 patients receiving 10 μg/kg fentanyl without any hypnotic agent and in 7 patients receiving 0.5 mg/kg propofol before the fentanyl dose. Results: The effect of fentanyl was very variable both regarding BIS and clinical response. Five of the 7 patients that received only fentanyl lost their response to verbal command within 8 min. BIS values at loss of response varied between 45 and 94. One patient remained awake with BIS 43. All 7 patients receiving propofol before the fentanyl dose lost their response to verbal command within 5 min. BIS values at the time for loss of response varied between 78 and 98. Conclusion: Loss of response to verbal command when a medium-high dose of fentanyl is used for induction cannot be distinguished from wakefulness with adequate sensitivity by BIS. The current BIS algorithm seems not to accurately reflect the hypnotic effects of fentanyl.

Risk factors for postoperative anxiety in children.

Abstract: Background: Anxiety is defined as a set of behavioural manifestations that can be divided into state- and trait-anxiety. State-anxiety is a transitory emotional condition that varies in intensity and fluctuates over time. Trait-anxiety is a personality trait which remains relatively stable over time. The objective of this study was to identify and quantify perioperative risk factors for immediate postoperative anxiety in children. Methods: A prospective cohort study was performed with 90 schoolchildren, ages ranging from 7 to 13 years old, ASA physical status I–II, submitted to elective surgery. The measuring instruments were verbal scale of pain, visual analogue scale (VAS), Trait-State Anxiety Inventory for Children (STAIC), Trait-State Anxiety Inventory (STAI) for parents, and structured questionnaire. Results: Patients not submitted to analgesic block and patients with moderate and intense pain presented an estimated risk 5- and 13-fold greater for high levels of postoperative state-anxiety, respectively. High levels of preoperative state-anxiety and administration of doses of midazolam less than 0.056 mg · kg−1 constituted an estimated risk for postoperative state-anxiety of 3- and 4-fold, respectively. A positive history of previous surgery was associated with lower risk for postoperative anxiety. Conclusions: High levels of preoperative state-anxiety, administration of less than 0.056 mg · kg−1 of midazolam, absence of analgesic block and presence of moderate and intense postoperative pain constituted risk factors for immediate postoperative state-anxiety in children. Previous surgery reduced the risk for postoperative anxiety.

Pain intensity and pain relief after surgery. A comparison between patients' reported assessments and nurses' and physicians' observations.

Abstract: Background: Postoperative pain remains a problem for many patients. One of the reasons could lie in the insufficient evaluation of pain and analgesia. This study was designed to obtain more insight in the performance of nurses and physicians in evaluating patients’ postoperative pain and pain relief. Methods: Forty patients hospitalised in one surgical unit and the 8 nurses and the 2 surgical residents in charge of this unit were investigated. Patients were asked to assess on a visual analogue scale the intensity of their pain and their pain relief at rest, on coughing and globally since the operation, on the first and second postoperative days and the day before hospital discharge. Separately, the nurses and the physicians were asked to evaluate the pain intensity and the pain relief for each patient involved. A MANOVA and a multiple comparisons test with Bonferroni adjustment were used. Results: At rest, only nurses underestimated pain intensity on the day before hospital discharge. On coughing, physicians underestimated pain intensity in all 3 assessments, whereas nurses only in the 3rd assessment (on the day before hospital discharge). Globally, physicians underestimated pain intensity in all 3 assessments, nurses in the 2nd and the 3rd assessment. Only physicians overestimated pain relief on coughing on the day before hospital discharge and globally in all 3 assessments. Surprisingly, the pain scores rated by the patients before hospital discharge were high. Conclusion: The results of this survey suggest that assessment of pain and pain relief is inadequately done by both physicians and nurses. This emphasises the importance of a better training, and a systematic assessment of pain intensity and pain relief.

Ropivacaine‐clonidine combination for caudal blockade in children

Abstract: Background: Adding clonidine to weak ropivacaine solutions (<0.2%) could potentially enhance analgesia as well as further reduce the risk for unwanted motor blockade. The aim of the present study was to compare the postoperative pain-relieving quality of a ropivacaine 0.1%-clonidine mixture to that of plain ropivacaine 0.2% following caudal administration in children. Methods: In a prospective, observer-blinded fashion, 40 ASA 1 paediatric patients undergoing subumbilical surgery were randomly allocated to receive a caudal injection of either plain ropivacaine 0.2% (1 ml/kg) (R0.2) or a mixture of ropivacaine 0.1% with clonidine 2 μg/kg (1 ml/kg) (R0.1C). Objective pain scale score and need for supplemental analgesia were used to evaluate analgesia during the first 24 h postoperatively. Residual postoperative sedation was also assessed. Results: A significantly higher number of patients in the R0.1C group (18/20) could be managed without supplemental analgesia during the first 24 h postoperatively compared to the R0.2 group (11/20) (P=0.034). Both the degree and the duration of postoperative sedation was similar in both groups. No signs of postoperative motor blockade were observed. Conclusions: The combination of clonidine (2 μg/kg) and ropivacaine 0.1% is associated with an improved quality of postoperative analgesia compared to plain 0.2% ropivacaine. The improved analgesic quality of the clonidine-ropivacaine mixture is achieved without causing any significant degree of postoperative sedation.

Remifentanil and propofol without muscle relaxants or with different doses of rocuronium for tracheal intubation in outpatient anaesthesia

Abstract: BACKGROUND The use of muscle relaxants in outpatient anaesthesia is controversial; some authors recommend an induction regimen including propofol and opioids without muscle relaxants. This study evaluated the requirements for rocuronium after remifentanil/propofol. METHODS We examined in four groups of ASA I-II patients (n= 30 for each) the intubating conditions three minutes after induction of anaesthesia with remifentanil 0.5 microg kg(-1) min(-1), propofol 2 mg kg(-1) without muscle relaxants or with different doses of rocuronium (0.6 mg kg(-1), 0.45 mg kg(-1), 0.3 mg kg(-1)) applying the criteria proposed by the Copenhagen Consensus Conference. In the second part of the study the time course of neuromuscular block was determined by electromyography using train-of-four (TOF) stimulation. To this end, another 60 ASA I-II patients were randomly assigned to receive remifentanil 0.5 microg kg(-1) min(-1), propofol 2 mg kg(-1) and either rocuronium 0.6 mg kg(-1), 0.45 mg kg(-1), 0.3 mg kg(-1), or 0.3 mg kg(-1) followed by neostigmine 40 microg kg(-1) and atropine 20 microg kg(-1) at a T1 recovery of 10% (n=15 for each). RESULTS Intubating conditions were good or excellent in 30 patients after rocuronium 0.6 mg kg(-1) and in 18 patients when rocuronium was omitted (P<0.01). After 0.45 mg kg(-1) and 0.3 mg kg(-1) rocuronium the numbers were 29 and 30 patients, respectively. Reducing rocuronium from 0.6 mg kg(-1) to 0.45 mg kg(-1) or 0.3 mg kg(-1) increased the onset time from 136 (35) s to 199 (34) s and 249 (52) s (mean (SD)), (P<0.01); the clinical duration decreased from 38 (10) min to 24 (8) min and 16 (5) min, respectively (P<0.01); and the duration to a TOF-ratio of 0.8 decreased from 60 (11) min to 45 (9) min and 34 (7) min (P<0.01). After rocuronium 0.3 mg kg(-1) this time interval further decreased to 22 (3) min when neostigmine was given at a T1 of 10% (P<0.01 compared with spontaneous recovery after rocuronium 0.3 mg kg(-1)). CONCLUSION After remifentanil/propofol intubation conditions were poor in 40% of patients without muscle relaxants; adding reduced doses of rocuronium to this regimen improved the intubation conditions significantly. In addition, reducing the initial dose of rocuronium markedly shortened its time course of action.

Local anaesthesia for awake fibreoptic nasotracheal intubation.

Abstract: Background: Awake fibreoptic nasotracheal intubation (FNI) is performed in potentially difficult airways under local anaesthesia. This observer-blinded study was designed to evaluate the efficacy of upper airway anaesthesia produced by nebulized lignocaine against combined regional block (CRB) for awake FNI. Methods: Forty-eight ASA 1 adults were randomly allocated to receive 4 ml of 4%-nebulized lignocaine (nebulization group) or translaryngeal block, bilateral superior laryngeal nerve block and three 4% lignocaine-soaked cotton swabs in the nose (CRB group). Facial grimace and patient comfort were assessed by grimace and airway reactivity scores. Patients reported their discomfort on a 4-point score. Results: All patients underwent successful FNI without significant discomfort; 79% in the nebulization group and 83% of the patients in the CRB group reported the procedure to be comfortable. A higher grimace score was recorded on insertion of the endotracheal tube (ETT) through the nostril in the nebulization group when compared to the CRB group, P<0.005. Similarly, patients in the CRB group were more comfortable during passage of the ETT into the glottis, as compared to the nebulization group. A progressive increase in heart rate was observed in all patients from the beginning of the procedure, but the rise in the nebulization group was greater, (P<0.05) and also lasted longer than in the CRB group (P<0.05). Mean arterial pressure was higher in the nebulization group when compared to the CRB group (P<0.05), with patients belonging to the CRB group demonstrating considerable haemodynamic stability. Conclusions: Both nebulization and CRB produced satisfactory anaesthesia of the upper airway, but CRB provided better patient comfort and haemodynamic stability.

Impact of acute renal failure on antioxidant status in multiple organ failure.

Abstract: Background: Acute renal failure (ARF) can be triggered or aggravated by reactive oxygen species (ROS) but established ARF per se might also affect the antioxidant defence mechanisms of the organism. We evaluated a broad pattern of antioxidants in critically ill patients with multiple organ failure with (MOF-ARF) and without acute renal failure (MOF) to identify any potential involvement of renal dysfunction in the depletion of the antioxidant system. Methods: Observational study; 13 patients with MOF were investigated (9 with and 4 without ARF), and 17 healthy subjects served as controls. Blood samples were drawn after establishment of MOF. Plasma levels of ascorbate, α-tocopherol, retinol, β-carotene, selenium and lipid peroxidation products (MDA) were determined and the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione-peroxidase (GSH-PX) in erythrocytes were measured. In addition, ROS production (superoxide anion and hydrogen peroxide) in activated neutrophils was assessed. Results: Plasma levels of ascorbate, β-carotene and selenium were reduced in both patient groups, when compared to controls. Decrease in selenium was more pronounced in the MOF-ARF group. MDA levels were increased in both groups, again being more pronounced in MOF-ARF patients compared to MOF patients. Hydrogen peroxide production by neutrophils from both patient groups was lower than from controls. Conclusion: A depression of the antioxidative system is present in critically ill patients with MOF. In patients with associated ARF this was even more pronounced and plasma MDA levels were higher, suggesting an additional effect on the antioxidative potential in the presence of renal dysfunction and/or renal replacement therapy.

Bispectral index, predicted and measured drug levels of target-controlled infusions of remifentanil and propofol during laparoscopic cholecystectomy and emergence

Abstract: Background Target-controlled infusions (TCI) have been launched as simple, accurate and reliable delivery systems of intravenous drugs. Bispectral index of EEG (BIS) seems promising in measuring hypnotic effect of anaesthetic drugs. The aims of this study were to evaluate the accuracy of TCI systems in patients undergoing laparoscopic cholecystectomy and to correlate measured drug levels to BIS values. Data were analysed for possible gender differences during emergence. Methods After written informed consent, 20 patients were enrolled in an open study. Remifentanil was set at 7.5 ng/ml as target throughout the whole procedure, and propofol at 5 microg/ ml at induction and 3 microg/ml after intubation. Values in blood samples of remifentanil and propofol were correlated to the estimated values and to systolic blood pressure and BIS. BIS values and measured drug levels during emergence and emergence time were compared for the two sexes. Results Measured drug values varied considerably from the set target with a prediction error of -22% for remifentanil and 49% for propofol. The anaesthesia level was regarded as quite deep with a mean BIS during stable surgery of 42 +/- 7, and at this level we found no correlation between measured values of either of the two drugs and BIS. The emergence time was significantly shorter for women (12.6 +/- 2.5 min) than for men (19.0 +/- 4.2 min) (P=0.001), with no significant differences in measured levels of propofol or remifentanil or BIS during the emergence period. Conclusion Present systems for TCI of remifentanil and propofol result in large intra- and interindividual variations in measured drug levels, and measured levels differ from target. There may be possible interaction between the two anaesthetics at a pharmacokinetic level. Within the level of anaesthesia studied here, BIS was not an indicator of the actual drug levels. Women woke up significantly faster than men.

Intraperitoneal lidocaine for postoperative pain after laparoscopy.

Abstract: Background: A controversy exists over the effectiveness and clinical value of intraperitoneal local anaesthetics for treating pain after laparoscopic cholecystectomy. The use of intraperitoneal lidocaine was evaluated in this study. Methods: At the end of surgery, 200 ml saline containing 200 mg lidocaine, or the same volume of saline, were randomly splashed under the right diaphragmatic surface in 50 patients in a double-blind manner. Postoperative shoulder and abdominal pain intensity were recorded on a numeric grading scale and a visual analogue scale, respectively. Analgesic consumption was also recorded. Respiratory function tests were compared before and after surgery. Side effects and recovery variables were assessed by the nurses at 2-h intervals. Results: The incidence, severity and duration of shoulder pain were reduced from 40% of patients scoring 3.9±0.2 for duration of 17.9±0.2 h in the control group to 12% scoring 2.5±0.5 for duration of 1.6±0.01 h in the lidocaine group. Lidocaine treated patients had significantly less abdominal postoperative pain immediately on return to the ward and during the first postoperative day (P<0.05). “No pain on deep inspiration” was reported by 72% of patients in the lidocaine group immediately on return to the ward compared to 8% of those in the control group. Analgesic consumption for 24 h after surgery was significantly less in the lidocaine group (P<0.05). There were no significant differences in respiratory function tests, recovery variables or incidence of side effects between the two groups. Conclusion: Intraperitoneal lidocaine is simple to use and results in a long-lasting reduction of pain after a single administration.

Bradycardia and asystolic cardiac arrest during spinal anaesthesia: A report of five cases

Abstract: Sudden, severe bradycardia/asystolic cardiac arrest are considered infrequent, but are certainly the most serious complications of spinal anaesthesia. We report four cases of primary asystole and one of severe bradycardia in young to middle-aged, healthy patients scheduled for minor surgery at the day surgery unit. Bradycardia/asystole were not related to respiratory depression or hypoxaemia/hypercarbia; they occurred at different time intervals after the onset of spinal anaesthesia (10-70 min) and, apparently, were not dependent on the level of sensory block, which varied between T3 and T8. One patient was nauseated seconds before the asystole, otherwise there was no warning signs. All the patients were easily resuscitated with the prompt administration of atropine and ephedrine and, in the case of cardiac arrest, cardiac massage and ventilation with oxygen. One patient was treated with a small dose of adrenaline. Four patients had the surgery, as planned; one had the surgery postponed. All the patients were discharged from hospital in good health and did not suffer any sequelae.

Droperidol and 5-HT3-receptor antagonists, alone or in combination, for prophylaxis of postoperative nausea and vomiting. A meta-analysis of randomised controlled trials.

Abstract: Background: Droperidol and 5-HT3-receptor antagonists are among the most potent antiemetics to prevent postoperative nausea and vomiting (PONV). Combinations of these drugs have been used to increase the efficacy of antiemetic treatment. However, so far the quantitative effect of this combination has not been evaluated systematically. Methods: Results from randomised controlled trials investigating the efficacy of 5-HT3-receptor antagonists or droperidol alone versus the combination of both drugs to prevent PONV were included in a meta-analysis. Studies were systematically searched using Medline, EMBASE, the Cochrane-Library, and by manually screening the reference lists of matching review articles and current issues of locally available peer-reviewed anaesthesia journals. Seven papers with data on granisetron published by Fujii and co-workers were not considered. The main end point in each study was defined as occurrence of nausea, retching, or vomiting within 6 h (“early PONV”) and within 48 h (“late PONV”) after surgery. The relative risks (RR) and the numbers needed to treat (NNT) of the pooled data with their corresponding 95% confidence intervals (given in parentheses) were calculated using a random effects model. Results: Eight studies with 881 patients (adults: n=801; children (mean age: 8 yr): n=80) were included in the analysis. Droperidol was applied to 340 patients, 5-HT3-receptor antagonists to 198, and 343 were treated with a combination of both drugs. Seven out of these eight studies reported increased antiemetic efficacy of the combination group compared with the single drugs (droperidol and 5-HT3-receptor antagonists respectively). However, in none of the trials did this difference reach statistical significance. When a meta-analytic analysis based on these results was performed the combination of droperidol with a 5-HT3-recpetor antagonist was not associated with a significantly increased antiemetic efficacy. In 12 to 13 patients a 5-HT3-receptor antagonist has to be added to droperidol prophylaxis to prevent one additional patient from PONV who would have had suffered from PONV when treated with droperidol alone (RR “early PONV”: 1.52 (0.95–2.44); RR “late PONV”: 1.24 (0.89–1.74)). Similar results were obtained when the antiemetic effect of adding droperidol to a prophylaxis with 5-HT3-receptor antagonists was analysed. In this case 10 to 12 patients have to be treated with the 5-HT3-droperidol combination instead of with a 5-HT3-receptor antagonist alone to prevent one additional patient from PONV (RR “early PONV”: 1.55 (0.68–3.52); RR “late PONV”: 1.29 (0.77–2.17)). There were no reports of an increased incidence of adverse effects. Conclusion: The data on the combination of droperidol with 5-HT3-receptor antagonists suggest that there is a trend towards increased efficacy of the combination therapy compared to the single drugs. However, so far there are insufficient data to recommend this combination treatment for prophylaxis.

The pharmacokinetics of anesthetic drugs and adjuvants during cardiopulmonary bypass.

Abstract: The institution of cardiopulmonary bypass during cardiac surgery has profound effects on the plasma concentration of drugs and thus their therapeutic effectiveness. These changes occur through acute hemodilution, altered plasma protein binding, hypotension, as well as the use of hypothermia and heparin administration. Isolation of the lungs from the circulation and the possible sequestration of drugs in the bypass circuit also affect drug plasma concentrations on bypass. The individual characteristics of the drug in question are also important in determining the final plasma concentration: Lipid soluble drugs with a high volume of distribution may be more readily taken up by bypass equipment, but the initial fall in concentration at the start of cardiopulmonary bypass may be more readily counteracted by back diffusion into plasma, if large tissue stores have accumulated. The extent of the drug's plasma protein binding is of importance as the effective free fraction in plasma for highly bound drugs will be sensitive to changes in plasma protein binding brought on by factors such as hemodilution, heparin administration as well as alpha, acid-glycoprotein binding. Clearly the fate of drugs administered before or on bypass is complex and can only be accurately determined by specific studies evaluating drug plasma concentrations. This review updates the available data on anesthetics and drugs used during cardiac surgery in order that anesthetists may predict better the likely effect of drugs administered before or during cardiopulmonary bypass.

Pre-incisional epidural ketamine, morphine and bupivacaine combined with epidural and general anaesthesia provides pre-emptive analgesia for upper abdominal surgery.

Abstract: Background: Previous studies have shown that N-methyl-D-asparate (NMDA) receptor antagonists provide a pre-emptive analgesic effect in humans. This study investigated the benefits of pre-emptive analgesia for upper abdominal surgery, using pre-incisional epidural ketamine + morphine + bupivacaine (K+M+B) treatment for achieving postoperative pain relief. Methods: Sixty ASA 1–2 patients scheduled for upper abdominal surgery were allocated to three groups in a randomized, single-blinded study. Patients in the control group (I) received general anaesthesia followed by an infusion of normal saline. Group II and III patients received general anaesthesia with a continuous epidural infusion of 2% lidocaine. Thirty minutes after the incision in groups I and II, an epidural pain control regimen was administered using ketamine (10 mg) and morphine (1 mg) in 10 ml of 0.085% bupivacaine (K+M+B). Group III patients also received K+M+B, but it was administered 10 min after the 2% lidocaine injection and 30 min before skin incision. All patients received an epidural pain control regimen (q12 h) for 3 days after their first injection. Patient-controlled analgesia (PCA) with morphine was used to control subsequent postoperative pain. During the 3-day period following surgery, duration to PCA trigger (h), morphine consumption (mg), pain intensity at rest and when coughing/moving, and analgesic-related adverse effects were recorded. The VAS scale (0–10) was used to assess pain intensity. Results: Median times to first PCA trigger were 1.2 (0.5–2.0) h, 3.0 (0.7–4.2) h, and 4.0 (2.5–7.5) h for groups I, II, and III, respectively. Both the incident and resting pain scores were consistently lower for group III patients than groups I and II. The number of PCA triggers (all attempts/successful triggers) during the day following surgery were 14.0 (3–30)/8.0 (3–24) times, 10.0 (3–23)/6.0 (2–20) times, and 7.0 (3–12)/4.5 (1–10) times for groups I, II, and III. Total morphine consumption for the 3-day observation period was 12.5 (3–42) mg, 10.5 (2–29) mg, and 6.0 (1–20) for groups I, II, and III, respectively. Conclusion: Pre-incisional epidural K+M+B treatment combined with continuous epidural anaesthesia and general anaesthesia provides an ideal pre-emptive analgesic therapy, exhibiting better postoperative pain relief than general anaesthesia and post-incisional K+M+B treatment.

Low-dose prostacyclin in treatment of severe brain trauma evaluated with microdialysis and jugular bulb oxygen measurements

Abstract: Background: The endogenous substance prostacyclin is a substance with the potential to improve microcirculation and oxygenation around contusions in the brain following a head trauma by its vasodilatory, antiaggregatory and antiadhesive effects. Microdialysis measurements of local concentrations of selected interstitial substances in the brain, and measurements of venous jugular bulb oxygenation reflecting overall brain oxygenation, might be useful to evaluate possible therapeutic effects of a specific therapy, such as treatment with prostacyclin. Methods: This case report study on six patients, of whom five were given prostacyclin, includes cerebral microdialysis measurements of interstitial lactate (n=5), pyruvate (n=3), glycerol (n=5) and glucose (n=4), and is combined with measurements of venous jugular bulb oxygenation in three of the patients. One microdialysis catheter was placed adjacent to a contusion, and in four of the patients another catheter was also placed in the contralateral less injured side for comparison. Low-dose prostacyclin infusion (0.5–1.0 ng kg−1 min−1) was started when lactate concentrations in the more injured side was raised at a constant level for more than 10 h. The study also includes one patient used as control to whom no prostacyclin was given. Results: Lactate was markedly lower in the less injured than in the more injured area of the brain. During the prostacyclin infusion elevated lactate and lactate/pyruvate ratio were reduced. Elevated glycerol decreased, a low glucose increased and jugular bulb blood oxygenation increased following start of prostacyclin. The control patient showed an increase in lactate and lactate/pyruvate ratio. Conclusion: The microdialysis data combined with the jugular bulb oxygenation data indicated that low-dose prostacyclin exerts effects compatible with improved oxygenation and reduced cell damage in the severely traumatised brain.

Epidural infusion of bupivacaine and fentanyl reduces perioperative myocardial ischaemia in elderly patients with hip fracture--a randomized controlled trial.

Abstract: Background: Perioperative myocardial ischaemia is an important risk factor for cardiac morbidity and mortality after noncardiac surgery. The impact of analgesic management on the incidence and severity of cardiac ischemia was studied in 77 elderly patients undergoing surgical treatment of traumatic hip fracture. Methods: After hospital admission and written consent, patients were randomised to conventional analgesic regimen (intramuscular oxycodone, OPI group) or continuous epidural infusion of bupivacaine/fentanyl (EPI group). The analgesic regimens were started preoperatively. Patients were operated under spinal anaesthesia and the treatments were continued three days postoperatively. ECG was continuously recorded. ST segment depression of ≥0.1 mV or elevation of ≥0.2 mV lasting ≥1 min were considered as ischaemic episodes. Nocturnal arterial oxygen saturation (SaO2) was recorded perioperatively, and subjective pain was assessed every morning using a visual analogue scale (VAS). Results: Fifty-nine (OPI 30, EPI 29) patients were evaluable for efficacy. Thirteen patients (43%) in the OPI and 12 patients (41%) in the EPI group had ischaemic episodes (NS). However, significantly more patients in the OPI group had ischaemic episodes during the surgery (8 vs. 0 in the EPI group, P=0.005). The median (quartal deviation) total ischaemic burden (i.e. integral of ST-change vs. time) in patients with ischaemic episodes was ten times larger in the OPI group (340 [342] mm · min) compared with the EPI group (30 [36] mm · min) (P=0.002). There were no significant differences between the groups in average heart rates or in heart rates at the start of ischaemic episodes or in maximal heart rates during the attacks. Average nocturnal SaO2 was similar in the two groups and there were no differences in the number of hypoxaemic (SaO2<90%) episodes. Preoperatively there were no differences in subjective pain, but postoperative and average perioperative VAS scores for pain were almost 40% lower in the EPI group (P=0.006). Perioperative myocardial infarctions were not detected. Conclusions: Continuous epidural bupivacaine/fentanyl analgesic regimen, started preoperatively, reduces the amount of myocardial ischaemia in elderly patients with hip fracture.

Regional anaesthesia for outpatient knee arthroscopy: a randomized clinical comparison of two different anaesthetic techniques

Abstract: BACKGROUND The purpose of this prospective, randomized study was to evaluate the time required to perform anaesthesia, achieve surgical block and fulfil standardized discharge criteria in outpatients receiving knee arthroscopy with either spinal anaesthesia or combined sciatic-femoral nerve block. METHODS After a standard midazolam/ketoprofen premedication and baseline measurement of cardiovascular parameters, 50 ASA I-II patients scheduled for elective outpatient knee arthroscopy were randomized to receive spinal anaesthesia with 8 mg of 0.5% hyperbaric bupivacaine (group Spinal, n=25), or combined sciatic-femoral nerve block with 25 ml of mepivacaine 20 mg ml(-1) and a multiple injection technique (15 ml for femoral nerve block and 10 ml for sciatic nerve block). Times lasting from skin disinfection to the end of local anaesthetic injection (preparation time) and then to achieve surgical anaesthesia (readiness for surgery), as well as times required for block resolution, micturition, unassisted ambulation, and home discharge were recorded by a blinded observer. Occurrence of adverse events was also recorded. RESULTS Preparation time (mean+/-SD) was longer with sciatic-femoral block (8+/-2.7 min) than spinal anaesthesia (5+/-2.1 min) (P=0.0002) while no differences were observed in the time required to achieve readiness for surgery (14+/-5 min and 15+/-6 min in the Spinal and Sciatic-femoral groups, respectively). No differences in haemodynamic side effects and need for intraoperative additional analgesia were observed. Patients receiving spinal anaesthesia showed a faster resolution of nerve block and longer time to micturition (137+/-49 min and 231+/-101 min) than patients receiving peripheral nerve blockade (206+/-51 min and 145+/-36 min) (P<0.0005 and P=0.002, respectively); however, no differences were observed in the time required to fulfil standardized discharge criteria (241+/-101 min in group Spinal and 209+/-70 min in group Sciatic-femoral; P=0.86). CONCLUSION In patients receiving elective outpatient knee arthroscopy, using a combined sciatic-femoral nerve block with 25 ml of mepivacaine 20 mg ml(-1) and a multiple injection technique results in a slightly longer preoperative time but provides similarly effective anaesthesia with no differences in home discharge times as compared to spinal anaesthesia with 8 mg hyperbaric bupivacaine.